Methods of coating substrates with electrically charged conductive materials, electrically conductive coated substrates, and associated apparatuses

Abstract

Methods include applying an electric charge to a coating material that includes carbon nanotubes and a carrier, such as paint, and depositing the electrically charged coating material to a substrate. In some methods, the applying includes utilizing an electrostatic sprayer. In some methods, the substrate is isolated from ground during the depositing. In some methods, the substrate is an insulator. Some methods result in regions of carbon nanotubes that are substantially longitudinally aligned after the depositing. Coated substrates may include a coating with carbon nanotubes that are substantially longitudinally aligned. Aircraft, spacecraft, land vehicles, marine vehicles, wind turbines, and apparatuses that may be susceptible to lightning strikes or other types of electromagnetic effects and that include a coated substrate also are disclosed.

The invention claimed is: 
     
       1. A method, comprising:
 applying an electric charge to a coating material to create an electrically charged coating material, wherein the coating material includes carbon nanotubes and a carrier; and 
 depositing the electrically charged coating material to a substrate to create a coated substrate, wherein during the depositing, the substrate is insulated from ground. 
 
     
     
       2. The method of  claim 1 , wherein the applying and the depositing includes spraying the coating material from an electrostatic sprayer. 
     
     
       3. The method of  claim 1 , wherein the substrate has an electrical resistivity of at least 10 9  Ohm meters at 20 degrees Celsius. 
     
     
       4. The method of  claim 1 , wherein the substrate has a surface resistivity of at least 10 9  Ohms/square. 
     
     
       5. The method of  claim 1 , wherein the carbon nanotubes are less than 5 weight percent of the coating material. 
     
     
       6. The method of  claim 1 , wherein the coated substrate has an electrical resistivity that is less than or equal to 90 percent of an electrical resistivity of the substrate prior to the depositing. 
     
     
       7. The method of  claim 1 , wherein the depositing results in regions of carbon nanotubes that are substantially aligned longitudinally relative to each other. 
     
     
       8. The method of  claim 7 , wherein the depositing results in longitudinal axes of at least 70 percent of the carbon nanotubes that are within a threshold angle of 10 degrees relative to each other. 
     
     
       9. The method of  claim 1 , wherein the depositing results in regions of carbon nanotubes that are arranged in a zig-zag pattern. 
     
     
       10. The method of  claim 9 , wherein longitudinal axes of the carbon nanotubes within a subset or region angle back and forth within a range of 120-180 degrees relative to longitudinally adjacent portions of the longitudinal axes. 
     
     
       11. The method of  claim 1 , wherein the depositing includes aligning subsets or regions of the carbon nanotubes in a predetermined configuration relative to the substrate to create a predetermined conductivity profile of the coated substrate. 
     
     
       12. The method of  claim 11 , wherein the predetermined conductivity profile is configured to effectuate electrical conductivity of the coated substrate. 
     
     
       13. The method of  claim 11 , wherein the predetermined conductivity profile is configured to effectuate electrostatic dispersal by the coated substrate. 
     
     
       14. The method of  claim 11 , wherein the predetermined conductivity profile is configured to absorb radar signals that are incident on the coated substrate. 
     
     
       15. The method of  claim 11 , wherein the predetermined conductivity profile is configured to define anisotropic conductivity of the coated substrate. 
     
     
       16. The method of  claim 1 , wherein the carrier is a resin carrier. 
     
     
       17. The method of  claim 1 , wherein the coating material is free of conducting metallic particles. 
     
     
       18. The method of  claim 1 , wherein the depositing includes depositing the electrically charged coating material to an external surface of an aircraft, a spacecraft, a land vehicle, a marine vehicle, or a wind turbine. 
     
     
       19. A method, comprising:
 spraying a coating material from an electrostatic sprayer on to a skin of an aircraft, wherein the coating material includes carbon nanotubes and a carrier, wherein the skin is constructed of a carbon fiber reinforced polymer and is not grounded during the spraying.